Various compositions are known to be useful as treating agents to provide surface effects to substrates. Surface effects include repellency to moisture, soil, and stains, and other effects, which are particularly useful for fibrous substrates and other substrates such as hard surfaces. Many such treating agents are fluorinated polymers or copolymers.
Siloxane- and fluorochemical-based compositions have been disclosed for the protection of hard substrate surfaces, e.g., mineral substrates, and for soft substrate surfaces, such as fibrous substrates. While siloxane-based treatments provide water repellency at a relatively low price per square meter and with good weathering resistance, they are marginal in oil repellency (for instance, see Stempf, A.; Muller, P.; Pabon, M.; Corpart, J. M. Int. J. Restoration Buildings & Monuments 1999, 5, 273-288). Fluorochemical-based treatments provide both oil and water repellency but are relatively expensive due to the necessary high fluorine content.
U.S. Pat. No. 6,503,313 disclosed a graft copolymer of a fluoro-polymer having at least one urethane linkage and containing at least one radically polymerizable unsaturated bond moiety and at least one polysiloxane, of which one terminal group was radically polymerizable. The compositions containing this graft copolymer composition are suitable for use as a coating having oil repellent, water repellent and stain resistant properties over a long period of time.
Most commercially available fluorinated polymers that are useful as treating agents for imparting repellency to substrates contain predominantly eight or more carbons in the perfluoroalkyl chain to provide the desired repellency properties. It is desirable to reduce the chain length of the perfluoroalkyl groups thereby reducing the amount of fluorine present, while still achieving the same or superior surface effects. There is a need for polymer compositions which significantly improve the repellency and stain resistance of fluorinated polymer treating agents for fibrous substrates and hard surface substrates while using lower levels of fluorine. The present invention provides such compositions.